How does population density affects transportation in Japan ?

Because of population Japan is used to busy rush hours and long traffic hours as well as many people boarding the subways during rush hours and because of that people may get trample or even loss a shoe so you may think that owning a car may be better but when having a car it can be difficult too you can't find a place to park it and they have to wait long hours on the streets due to traffic because of these complications japan has a strict law that says you can't buy a car unless you can show you can park it off the streets and the subways have hire workers to push people in to the subways to make sure all carts run on time since time is valuable in japan so every person can aboard the subway